Well, if somebody tells me that the code I wrote fails in a certain
manner it is very probable that I as the author know where to look.
I expected the authors of the package that created the diff would
be easily able to track down the problem.

It's the simplest and most direct way to test your hypothesis that
that particular package update is the cause of your problem.

This is kind of strategy of a scientist doing investigation in a
field that is unknown so far. While it is really unknown for me
there are people who are comfortable in understanding what happens
because they invented this stuff.

(And, yes
it _it_ the clever way to start, rather than trying to dig into code
changes that may and may not be related to the effect you're seeing).

For me it is not really clever but the only chance. There is no
real cleverness in it - but finally this is of topic here to discuss.
If I will get no further comments until weekend I will start with
the digging.
Kind regards
Andreas.
--
http://fam-tille.de